The present invention relates to a kind of pump, and more specifically relates to a swing barrel type positive displacement pump.
Swing barrel type positive displacement pump currently available in the market comprises a main shaft connected with a motor. An upper part of the main shaft is slantwise provided with a rotating barrel which swings along with the rotation of the main shaft. Periphery of the rotating barrel is evenly provided with more than three displacement chambers and these displacement chambers form a pump cylinder. Outside the rotating barrel there is evenly provided with ball bearings. Bottom parts of the ball bearings are connected with one end of a connecting bar. Another end of the connecting bar adopts a ball shape and movably connects with a piston disposed inside the displacement chambers. The positive displacement pump according to the prior art transforms the rotational movement of the main shaft to vertical movement of the piston inside the displacement chambers via the swinging of the rotating barrel. The positive displacement pump according to the prior art can satisfactorily meet the requirements for a high-lift submersible pump in deserts or plateau. However, since the ball bearings outside the rotating barrel adopt the structure of sliding bearings which produce sliding friction with high coefficient of friction during operation, the ball bearings cannot satisfactorily perform efficient transmission of motion. Also, wearing of the ball bearings will increase the frequency of maintenance of the pump and thus shorten the life of the pump.